1. Field of the Invention
The present invention relates to a cassette for tape material.
More particularly, but not exclusively, the invention relates to a cassette for light-sensitive tape material.
The terms "tape" and "tape material" are used herein in their broad sense of referring to any kind of flexible, strip-shaped sheet material.
2. The Prior Art
In many instances cassettes are required to contain light-sensitive tape material which must be protected against the access of light. For example, automatic equipment for copying of films or photos, and printing equipment for picture-to-picture copying on image-reversing photosensitive paper, requires the use of light-sensitive paper strips or tapes. For convenience of handling the rolls of paper are accommodated in so-called "daylight cassettes" i.e., cassettes which prevent any access of light to the tape in their interior. This makes it possible to insert the cassette in the machine in daylight, and also to remove it again under the same conditions.
The leading end portion (having a length of usually a few centimeters) extends out from the cassette at the time the same is inserted into the machine. This is necessary because this end portion must be threaded through the machine and inserted into an empty take-up cassette into which the tape is transferred during operation of the machine. This insertion of the leading tape end portion into the empty cassette is cumbersome and time consuming, because the empty cassette must first be opened, the tape end portion inserted into a slot in the take-up hub of the cassette (or clamped behind a spring clamp) and the cassette then be closed again.
Another type of cassette which has been proposed and which seeks to overcome the problem by having the user merely insert the tape end through a slot, whereupon it is then automatically taken up on the hub, can be used only for take-up purposes. It can not be used to subsequently pay the tape out again so that difficulties are created in retrieval of the tape from the cassette and also in terms of having to keep two different types of cassettes on hand (i.e., take-up and pay-out cassettes). Attempts to make such cassettes suitable for pay-out as well have been unsuccessful because the necessary measures raise the cost of the cassette to an economically not acceptable level.
There is a type of daylight cassette known which can be used for both take-up and pay-out. In this, an annulus of pins is located in the interior and cooperate with a similar second annulus of pins. The tape end is inserted from outside through the pins of these annuli and the latter are then displaced relative to one another until they clamp the tape end between them. This, however, is also an economically unattractice construction.